1. Field of Invention
This invention relates to a device for simultaneous frequency modulation and amplification and it is particularly related to a device which is capable of putting out an amplified reproduction of an input signal while modulating the same simultaneously. More specifically, this invention relates to a device which is sensitive to low frequencies and which is capable of amplifying low frequency sounds.
2. The Prior Art
So far as it is known, most prior art devices which have heretofore been used for amplification of low frequency sounds have been high frequency amplifiers which are not capable of amplifying low frequency sounds without simultaneously overamplifying the surrounding high frequency sounds. A typical example of a high frequency amplifier is the well known electron microphone with a microphone pick-up, and a typical low power amplifier is the well known physician stethoscope which is commonly employed to listen to the human heart. Such stethoscopes, however, while capable of detecting low frequency sounds, have limited amplification capacity. It is frequently desirable, however, to amplify low frequency sounds without overamplifying the surrounding high frequency sounds, in order to derive valuable information, such as, for example, when listening to the human heart beat.
The device of this invention is not only capable of detecting the human heart beat, but it has the unique capability of detecting and amplifying the low frequency sounds associated therewith, such as the sound associated with the flow of blood in the human system.